1. Field of the invention
The present invention relates to new and useful improvements in squeeze tubes and for accessories therefor, and concerns elongated squeeze tubes of the type for containing and for controllably dispensing viscous or plastically flowable contents thereof through a normally closed dispensing opening at one end that can be selectively opened to allow the flow of a volume of tube contents corresponding to the amount that the tube is squeezed. More specifically, the invention is concerned with a procedure or method of and structure enabling the squeezing of a tube so that, in a progressive fashion, the tube is preferentially voided of its contents most remote from the opening with the voided extent of the tube being rolled and retained in a rolled condition at one side of the immediately adjacent, yet to be voided, portion of the tube.
2. Description of Related Art
Squeeze tubes have been widely known and used for many years, and have typically been largely thin walled structures made of malleable, ductile or plastic alloys of metals such as aluminum, lead, tin, etc., having little if any elasticity or resilience. Recently, however, squeeze tubes have been made of flexible synthetic resins or plastics.
Customary usage of metallic squeeze tubes entailed squeezing the end of the tube remote from the dispensing opening, and concurrently or thereafter rolling up the collapsed portion of the tube. Many users, much to the dispair of others, simply squeezed the tube and neglected to roll the tube despite appearances, and others had to content themselves with the hope that the slothful or careless user would recap the tube after use to prevent leakage or tube content contamination.
Quite often, users of the metallic tubes were provided with a finger-operated winding key to facilitate neat and uniform rolling that was often difficult to achieve.
With the advent of the transition from metallic to plastic for synthetic squeeze tubes, a new set of problems arose in connection with such tubes having considerable elasticity and a pronounced tendency for the tube wall to return to or approach its initial configuration when the tube was full.
While the elastic plastic tubes enjoy the advantage of presenting an external surface of smooth and rounded contours, and never having the appearance of a tin can that has been the object of boys playing stick hockey in the street, such tubes do not share an important advantage of metallic tubes, namely, the substantially total absence of voids within the tube.
Though a plastic tube may be initially free of voids, voids therein will occur on any restoration of initial tube configuration after having been partially squeezed. Such restoration not only makes the actual remainder of tube contents deceptive to visual inspection (a nearly empty plastic tube may appear full), but worse, air with its microscopic contaminants such as bacteria, spores, yeast, etc., can enter the tube and deleteriously affect tube contents.
Keys of various forms to facilitate plastic tube rolling have been proposed, but these ordinarily project laterally from the tube to a degree deemed objectionable by many, but worse, the elastic tubes tend to unroll the rolling that may have already been accomplished.